Fracture resistance of chairside cad/cam advanced lithium disilicate maxillary canine veneers with different incisal edge designs.

Abstract

This study aimed to evaluate the fracture resistance of maxillary veneers with feather edge, butt-joint and palatal chamfer and traditional full coverage crowns fabricated out of chairside CAD/CAM advanced lithium disilicate and virgilite. Fifty-two restorations for maxillary right canine were fabricated (n = 13 per group) as follows: veneers with feather edge, veneers with butt-joint, veneers with palatal chamfer and full coverage crowns out of chairside CAD/CAM lithium disilicate and virgilite (Cerec Tessera). The restorations were bonded to 3D printed resin dies with resin cement (Variolink Esthetic LC). The cemented restorations were subjected to 10,000 thermocycles at 5 to 55 °C with a dwell time of 30 s. The specimens were loaded until fracture using a universal testing machine and the resistance was recorded in Newtons. Two-way ANOVA was used to assess the fracture resistance among veneers with different incisal edge designs and between veneers and crowns. Scanning electron microscope (SEM) images of the fractured specimens were taken and descriptive analysis was carried out. Full coverage crowns displayed higher fracture resistance (1496 ± 41 N) than any type of veneers. Veneers with palatal chamfer showed the highest value (842 ± 28 N) among veneers followed by butt joint veneers (661 ± 22 N). Feather edge veneers provided the lowest fracture resistance values (464 ± 23 N). The fracture resistance of CAD/CAM advanced lithium disilicate maxillary veneers are significantly influenced by the incisal edge design. Palatal chamfer veneers displayed higher fracture resistance than feather edge and butt joint veneers. Full coverage crowns offered higher fracture resistance than any type of veneer.